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Copy pathmod.rs
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366 lines (317 loc) · 12.2 KB
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use core::fmt;
use std::fmt::{Debug, Formatter};
use std::ops::{Index, IndexMut};
use crate::err::{Error, ErrorType, ProcessingResult, debug_repr};
use crate::proc::MatchAction::*;
use crate::proc::MatchMode::*;
use crate::proc::range::ProcessorRange;
use memchr::memchr;
use crate::gen::codepoints::Lookup;
#[cfg(feature = "js-esbuild")]
use std::sync::{Arc, Mutex};
#[cfg(feature = "js-esbuild")]
use esbuild_rs::TransformResult;
#[cfg(feature = "js-esbuild")]
use crossbeam::sync::WaitGroup;
pub mod checkpoint;
pub mod entity;
pub mod range;
pub enum MatchMode {
IsChar(u8),
IsNotChar(u8),
WhileChar(u8),
WhileNotChar(u8),
// Through is like WhileNot followed by Is, but matches zero if Is is zero.
ThroughChar(u8),
IsPred(fn(u8) -> bool),
IsNotPred(fn(u8) -> bool),
WhilePred(fn(u8) -> bool),
WhileNotPred(fn(u8) -> bool),
IsInLookup(&'static Lookup),
WhileInLookup(&'static Lookup),
WhileNotInLookup(&'static Lookup),
IsSeq(&'static [u8]),
}
pub enum MatchAction {
Keep,
Discard,
MatchOnly,
}
#[cfg(feature = "js-esbuild")]
pub struct JsMinSection {
pub src: ProcessorRange,
pub result: TransformResult,
}
// Processing state of a file. Single use only; create one per processing.
pub struct Processor<'d> {
code: &'d mut [u8],
// Index of the next character to read.
read_next: usize,
// Index of the next unwritten space.
write_next: usize,
#[cfg(feature = "js-esbuild")]
script_wg: WaitGroup,
#[cfg(feature = "js-esbuild")]
script_results: Arc<Mutex<Vec<JsMinSection>>>,
}
impl<'d> Index<ProcessorRange> for Processor<'d> {
type Output = [u8];
fn index(&self, index: ProcessorRange) -> &Self::Output {
&self.code[index.start..index.end]
}
}
impl<'d> IndexMut<ProcessorRange> for Processor<'d> {
fn index_mut(&mut self, index: ProcessorRange) -> &mut Self::Output {
debug_assert!(index.end <= self.write_next);
&mut self.code[index.start..index.end]
}
}
impl<'d> Processor<'d> {
// Constructor.
pub fn new(code: &mut [u8]) -> Processor {
Processor {
write_next: 0,
read_next: 0,
code,
#[cfg(feature = "js-esbuild")]
script_wg: WaitGroup::new(),
#[cfg(feature = "js-esbuild")]
script_results: Arc::new(Mutex::new(Vec::new())),
}
}
// INTERNAL APIs.
// Bounds checking.
fn _in_bounds(&self, offset: usize) -> bool {
self.read_next + offset < self.code.len()
}
// Reading.
/// Get the `offset` character from next.
/// When `offset` is 0, the next character is returned.
/// Panics. Does not check bounds for performance (e.g. already checked).
fn _read_offset(&self, offset: usize) -> u8 {
self.code[self.read_next + offset]
}
fn _maybe_read_offset(&self, offset: usize) -> Option<u8> {
self.code.get(self.read_next + offset).map(|c| *c)
}
fn _maybe_read_slice_offset(&self, offset: usize, count: usize) -> Option<&[u8]> {
self.code.get(self.read_next + offset..self.read_next + offset + count)
}
/// Move next `amount` characters to output.
/// Panics. Does not check bounds for performance (e.g. already checked).
#[inline(always)]
fn _shift(&mut self, amount: usize) -> () {
// Optimisation: Don't shift if already there (but still update offsets).
if self.read_next != self.write_next {
self.code.copy_within(self.read_next..self.read_next + amount, self.write_next);
};
self.read_next += amount;
self.write_next += amount;
}
#[inline(always)]
fn _replace(&mut self, start: usize, end: usize, data: &[u8]) -> usize {
debug_assert!(start <= end);
let added = data.len() - (end - start);
// Do not allow writing over source.
debug_assert!(self.write_next + added <= self.read_next);
self.code.copy_within(end..self.write_next, end + added);
self.code[start..start + data.len()].copy_from_slice(data);
// Don't need to update read_next as only data before it has changed.
self.write_next += added;
added
}
#[inline(always)]
fn _insert(&mut self, at: usize, data: &[u8]) -> usize {
self._replace(at, at, data)
}
// Matching.
#[inline(always)]
fn _one<C: FnOnce(u8) -> bool>(&mut self, cond: C) -> usize {
self._maybe_read_offset(0).filter(|n| cond(*n)).is_some() as usize
}
#[inline(always)]
fn _many<C: Fn(u8) -> bool>(&mut self, cond: C) -> usize {
let mut count = 0usize;
while self._maybe_read_offset(count).filter(|c| cond(*c)).is_some() {
count += 1;
};
count
}
fn _remaining(&self) -> usize {
self.code.len() - self.read_next
}
#[inline(always)]
pub fn m(&mut self, mode: MatchMode, action: MatchAction) -> ProcessorRange {
let count = match mode {
IsChar(c) => self._one(|n| n == c),
IsNotChar(c) => self._one(|n| n != c),
WhileChar(c) => self._many(|n| n == c),
WhileNotChar(c) => memchr(c, &self.code[self.read_next..]).unwrap_or(self._remaining()),
ThroughChar(c) => memchr(c, &self.code[self.read_next..]).map_or(0, |p| p + 1),
IsInLookup(lookup) => self._one(|n| lookup[n]),
WhileInLookup(lookup) => self._many(|n| lookup[n]),
WhileNotInLookup(lookup) => self._many(|n| !lookup[n]),
IsPred(p) => self._one(|n| p(n)),
IsNotPred(p) => self._one(|n| !p(n)),
WhilePred(p) => self._many(|n| p(n)),
WhileNotPred(p) => self._many(|n| !p(n)),
IsSeq(seq) => self._maybe_read_slice_offset(0, seq.len()).filter(|src| *src == seq).map_or(0, |_| seq.len()),
};
// If keeping, match will be available in written range (which is better as source might eventually get overwritten).
// If discarding, then only option is source range.
let start = match action {
Discard | MatchOnly => self.read_next,
Keep => self.write_next,
};
match action {
Discard => self.read_next += count,
Keep => self._shift(count),
MatchOnly => {}
};
ProcessorRange { start, end: start + count }
}
// PUBLIC APIs.
// Bounds checking
pub fn at_end(&self) -> bool {
!self._in_bounds(0)
8000
}
pub fn require_not_at_end(&self) -> ProcessingResult<()> {
if self.at_end() {
Err(ErrorType::UnexpectedEnd)
} else {
Ok(())
}
}
/// Get how many characters have been consumed from source.
pub fn read_len(&self) -> usize {
self.read_next
}
pub fn reserve_output(&mut self, amount: usize) -> () {
self.write_next += amount;
}
// Looking ahead.
/// Get the `offset` character from next.
/// When `offset` is 0, the next character is returned.
pub fn peek(&self, offset: usize) -> Option<u8> {
self._maybe_read_offset(offset)
}
pub fn peek_many(&self, offset: usize, count: usize) -> Option<&[u8]> {
self._maybe_read_slice_offset(offset, count)
}
// Looking behind.
pub fn last(&self, count: usize) -> &[u8] {
self.code.get(self.write_next - count..self.write_next).unwrap()
}
// Consuming source characters.
/// Skip and return the next character.
/// Will result in an error if exceeds bounds.
pub fn skip(&mut self) -> ProcessingResult<u8> {
self._maybe_read_offset(0).map(|c| {
self.read_next += 1;
c
}).ok_or(ErrorType::UnexpectedEnd)
}
pub fn skip_amount_expect(&mut self, amount: usize) -> () {
debug_assert!(!self.at_end(), "skip known characters");
self.read_next += amount;
}
pub fn skip_expect(&mut self) -> () {
debug_assert!(!self.at_end(), "skip known character");
self.read_next += 1;
}
// Writing characters directly.
/// Write `c` to output. Will panic if exceeds bounds.
pub fn write(&mut self, c: u8) -> () {
self.code[self.write_next] = c;
self.write_next += 1;
}
pub fn write_range(&mut self, s: ProcessorRange) -> ProcessorRange {
let dest_start = self.write_next;
let dest_end = dest_start + s.len();
self.code.copy_within(s.start..s.end, dest_start);
self.write_next = dest_end;
ProcessorRange { start: dest_start, end: dest_end }
}
/// Write `s` to output. Will panic if exceeds bounds.
pub fn write_slice(&mut self, s: &[u8]) -> () {
self.code[self.write_next..self.write_next + s.len()].copy_from_slice(s);
self.write_next += s.len();
}
pub fn write_utf8(&mut self, c: char) -> () {
let mut encoded = [0u8; 4];
self.write_slice(c.encode_utf8(&mut encoded).as_bytes());
}
// Shifting characters.
pub fn accept(&mut self) -> ProcessingResult<u8> {
self._maybe_read_offset(0).map(|c| {
self.code[self.write_next] = c;
self.read_next += 1;
self.write_next += 1;
c
}).ok_or(ErrorType::UnexpectedEnd)
}
pub fn accept_expect(&mut self) -> u8 {
debug_assert!(!self.at_end());
let c = self._read_offset(0);
self.code[self.write_next] = c;
self.read_next += 1;
self.write_next += 1;
c
}
pub fn accept_amount_expect(&mut self, count: usize) -> () {
debug_assert!(self._in_bounds(count - 1));
self._shift(count);
}
#[cfg(feature = "js-esbuild")]
pub fn new_script_section(&self) -> (WaitGroup, Arc<Mutex<Vec<JsMinSection>>>) {
(self.script_wg.clone(), self.script_results.clone())
}
// Since we consume the Processor, we must provide a full Error with positions.
#[cfg(not(feature = "js-esbuild"))]
pub fn finish(self) -> Result<usize, Error> {
debug_assert!(self.at_end());
Ok(self.write_next)
}
// Since we consume the Processor, we must provide a full Error with positions.
#[cfg(feature = "js-esbuild")]
pub fn finish(self) -> Result<usize, Error> {
debug_assert!(self.at_end());
self.script_wg.wait();
let mut results = Arc::try_unwrap(self.script_results)
.unwrap_or_else(|_| panic!("failed to acquire script results"))
.into_inner()
.unwrap();
results.sort_unstable_by_key(|r| r.src.start);
// As we write minified JS code for sections from left to right, we will be shifting code
// towards the left as previous source JS code sections shrink. We need to keep track of
// the write pointer after previous compaction.
// If there are no script sections, then we get self.write_next which will be returned.
let mut write_next = results.get(0).map_or(self.write_next, |r| r.src.start);
for (i, JsMinSection { result, src }) in results.iter().enumerate() {
// Resulting minified JS to write.
// TODO Verify.
// TODO Rewrite these in esbuild fork so we don't have to do a memcpy and search+replace.
let min_js = result.js.trim().replace("</script", "<\\/script");
let js_len = if min_js.len() < src.len() {
self.code[write_next..write_next + min_js.len()].copy_from_slice(min_js.as_bytes());
min_js.len()
} else {
// If minified result is actually longer than source, then write source instead.
// NOTE: We still need to write source as previous iterations may have shifted code down.
self.code.copy_within(src.start..src.end, write_next);
src.len()
};
let write_end = write_next + js_len;
let next_start = results.get(i + 1).map_or(self.write_next, |r| r.src.start);
self.code.copy_within(src.end..next_start, write_end);
write_next = write_end + (next_start - src.end);
};
Ok(write_next)
}
}
impl Debug for Processor<'_> {
fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
f.write_str(&debug_repr(self.code, self.read_next as isize, self.write_next as isize))?;
Ok(())
}
}